Synthesis of centimeter-scale WS2 membrane by chemical vapor deposition

Transition metal dichalcogenides (TMDCs) are among the most widely studied two-dimensional materials due to their unique physical properties, but synthesis of large area of monolayer TMDCs films is still a great challenge. In this study, a simple and universal promoter-assisted chemical vapor deposition (CVD) method is proposed for the synthesis of centimeter-scale of Tungsten disulfide (WS2) membranes. The highly volatile transition metal halides formed by the reaction of Tungstic acid (H2WO4) and Sodium chloride (NaCl) effectively reduces the growth temperature of WS2, and the vulcanization energy barrier for the growth of WS2 monolayer, thus improve the growth rate along the in-plane direction. By optimizing the experimental parameters, high quality of WS2 films in centimeter-sizes are prepared. This study provides a method for the preparation of large-scale WS2 films and lays a foundation for the industrial application of large-scale two-dimensional materials.